Apparatus and method for determining the relative position of bones during surgery

ABSTRACT

A measuring gauge for measuring the relative position of two bones during surgery, the measuring gauge comprising an anchor, an adapter, an outrigger and a locking joint.

REFERENCE TO PENDING PRIOR PATENT APPLICATION

This is a continuation of prior U.S. Pat. No. 6,193,724 application Ser.No. 09/200,127, filed Nov. 25, 1998 is now by Kwan-Ho Chan for APPARATUSAND METHOD FOR DETERMINING THE RELATIVE POSITION OF BONES DURINGSURGERY.

FIELD OF THE INVENTION

This invention relates to surgical apparatus and procedures in general,and more particularly to surgical apparatus and procedures fordetermining the relative position of bones during surgery, and stillmore particularly to surgical apparatus and procedures for determiningthe distal displacement and lateral offset of a patient's femur relativeto that patient's ilium during total hip replacement surgery.

BACKGROUND OF THE INVENTION

Unacceptable leg length inequalities, mis-sized lateral offsets, andjoint dislocations are possible adverse outcomes of total hipreplacement surgeries. Leg length inequalities and mis-sized lateraloffsets (including, particularly, insufficient lateral offsets) canresult in a persistent limp for patients who have undergone total hipreplacement surgeries. Also, joint dislocations are more likely to occurif the soft tissue tension across the replaced joint is too lax as aresult of a shortened limb and/or an insufficient lateral offset.

It is, therefore, generally desirable to maintain the leg length, andthe amount of lateral offset, which existed prior to the total hipreplacement surgery. Sometimes, however, it may he desirable duringtotal hip replacement surgery to change the leg length, and/or theamount of lateral offset, so as to compensate for deficiencies existingin the hip joint prior to the total hip replacement surgery.

The desired leg length, and the desired lateral offset, are achievedduring the total hip replacement surgery by selecting a femoral headprosthesis which has the appropriate neck length and geometry, and/or byvarying the amount of bone resection performed on the femur.

To achieve the desired leg length and lateral offset during total hipreplacement surgery, the surgeon typically determines the initial (i.e.,pre-dislocation) position of the femur relative to the ilium, based onreference points selected on each of these bones. A number of differentdevices and methods for measuring the position of the femur relative tothe ilium are known in the art. These existing devices and methods aregenerally used in conjunction with one or more reference pins which areinserted into a convenient location in the ilium, e.g., typically a fewcentimeters above the acetabulum. The position of the patient's femur isthen measured off the aforementioned one or more reference pins, bymeasuring to an appropriate reference point on the femur, e.g.,typically in the area of the greater trochanter. It should beappreciated that the femoral reference point is typically located in thearea of the greater trochanter inasmuch as the greater trochanter is notremoved during femoral resection, yet is on the upper part of the femurand hence reasonably close to the patient's ilium so as to facilitatemeasurement.

By way of example, various devices and methods for measuring theposition of the femur relative to the ilium are disclosed in U.S. Pat.Nos. 5,122,145; 5,423,828; 5,435,321; 5,603,717; 5,616,147; 5,700,268;and 5,755,794.

Unfortunately, however, all of the existing devices and methods formeasuring the position of the femur relative to the ilium tend to sufferfrom one or more significant disadvantages. On the one hand, some of theexisting devices only measure the longitudinal displacement of thefemur, and they do not measure the lateral offset of the femur. On theother hand, in those devices which can measure both the longitudinaldisplacement and lateral offset of the femur, the devices tend to berelatively bulky and complicated to install and use.

OBJECTS OF THE INVENTION

Accordingly, one object of the present invention is to provide animproved apparatus for simultaneously determining the distaldisplacement and lateral offset of the femur relative to the ilium.

Another object of the present invention is to provide an apparatus forsimultaneously determining the distal displacement and lateral offset ofthe femur relative to the ilium, wherein the apparatus is adapted foreasy installation and removal, whereby a major portion of the apparatuscan be temporarily removed from the surgical site so as to provideunobstructed access to the surgical site.

And another object of the present invention is to provide an apparatusfor simultaneously determining the distal displacement and lateraloffset of the femur relative to the ileum, wherein the apparatus is safeand effective for use in total hip replacement surgeries.

Still another object of the present invention is to provide an apparatusfor determining the distal displacement and lateral offset of the femurrelative to the ileum, wherein the apparatus will reduce the amount oftime normally required to determine the distal displacement and lateraloffset of the femur relative to the ileum.

Yet another object of the present invention is to provide an apparatusfor determining the relative position of bones during surgery, whereinthe bones may comprise bones other than the femur and the ileum.

And another object of the present invention is to provide an improvedmethod for measuring the distal displacement and lateral offset of thefemur relative to the ilium.

And another object of the present invention is to provide an improvedmethod for determining the relative position of bones during surgery.

SUMMARY OF THE INVENTION

These and other objects of the present invention are addressed by theprovision and use of a novel measuring gauge for determining therelative position of bones during surgery.

The novel measuring gauge comprises an anchor, preferably made ofstainless steel, having a pointed tip for insertion into, and temporaryattachment to, the ilium of the patient. A stop is preferably located onthe anchor about 1 to 3 centimeters from the pointed tip. The stopprevents excessive penetration of the anchor into the ilium, which mightinjure internal organs or neurovascular structures.

An adapter slidingly engages the anchor and sits atop the stop. Thepointed tip of the anchor is driven into the ilium bone at a convenientlocation, usually a few centimeters above the acetabulum. The pointedtip can be driven into the bone by impacting the anchor directly, or byimpacting the adapter mounted on the anchor.

An outrigger, comprising a shaft which preferably has a pointer at oneend, is adjustably connected to the adapter by a releasable lockingjoint. The outrigger's pointer preferably projects at a right angle tothe longitudinal axis of the outrigger.

In use, after surgical exposure of the hip joint, and prior to thedislocation of the joint for bone resection, a reference mark,preferably one to two millimeters deep, is made at a convenient locationon the greater trochanter of the femur using a sharp pointed device suchas the tip of a pin. Alternatively, the reference mark can be made witha marking pen or an electrocautery device. The anchor (with or withoutthe adapter mounted thereon) is positioned in the ilium as describedabove.

Next, the elements of the measuring gauge are arranged so that theoutrigger is adjustably connected to the adapter by the releasablelocking joint, with the adapter being seated on the anchor. The tip ofthe pointer can then be positioned in three dimensional space, using thefollowing degrees of freedom of the adapter, locking joint andoutrigger: (1) the locking joint, together with the outrigger, isslidable along the longitudinal axis of the adapter; (2) the lockingjoint and outrigger can also rotate about the longitudinal axis of theadapter and/or about the longitudinal axis of the anchor; (3) the shaftof the outrigger can also telescope in and out of the locking joint; and(4) the outrigger can also rotate around the long axis of its shaft.

Using the aforementioned degrees of freedom, the measuring gauge ismanipulated so that the outrigger's pointer is positioned over thereference mark on the femur. At this stage, the adapter and outriggerare securely locked together, in a fixed relative position, by firmlytightening the locking joint. In this manner, the position of thereference mark on the femur, relative to the anchor installed on theilium, is clearly established vis-à-vis the elements of the measuringgauge.

Thereafter, the adapter, locking joint and outrigger are slidinglydisengaged from the anchor, as a locked unit, so as to provide thesurgeon with unobstructed access to the hip joint.

The hip joint is then dislocated for resection of the appropriate amountof femoral bone.

Following initial preparation of the bone bed, a trial prosthesis isinstalled in the patient's femur. This initial trial prosthesis isselected by the surgeon, from an assortment of different prostheses,according to the surgeon's initial estimate of which prosthesis willachieve the desired results.

The hip joint is then reduced so that the surgeon can check for properalignment of the prosthesis, any leg length discrepancy, proper lateraloffset, and the stability of the hip joint from dislocation. Moreparticularly, after the hip joint has been reduced, the surgeonrepositions the adapter, locking joint and outrigger, as a locked unit,over the anchor. This permits the surgeon to check for proper distaldisplacement and lateral offset of the femur relative to the ilium, byobserving any displacement of the outrigger's pointer from the referencemark placed on the femur's greater trochanter.

In the usual case, i.e., where the original geometry of the patient'sjoint was correct and is to be maintained during the total hipreplacement surgery, an appropriate prosthesis will be selected so as toensure that the outrigger's pointer is substantially aligned with thereference mark placed on the femur's greater trochanter.

In other cases, however, the geometry of the patient's joint is to bechanged during the total hip replacement surgery, by varying the distaldisplacement and/or lateral offset of the femur relative to the ilium.In this case, the desired joint correction is achieved by selecting anappropriate femoral prosthesis so as to ensure that the outrigger'spointer is displaced a desired distance from the reference mark placedon the femur's greater trochanter.

After the surgeon has noted the position of the outrigger's pointerrelative to the reference mark placed on the femur's greater trochanter,the adapter, locking joint and outrigger are then removed, again as alocked unit.

The joint is then dislocated once more, the trial prosthesis is removed,and the permanent prosthesis installed. As noted above, the desiredamount of distal displacement and lateral offset is achieved bycarefully choosing a prosthesis component of the proper size andgeometry, and/or by varying, where possible, the amount of bone which isresected.

After the trial prosthesis has been replaced by the permanentprosthesis, the joint is reduced, and a final check of the joint can bemade with the measuring gauge.

Prior to wound closure, the measuring gauge, including the anchorfastened to the ilium, is removed from the surgical site.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiment of the invention, which is to beconsidered together with the accompanying drawings wherein like numbersrefer to like parts and further wherein:

FIG. 1 is a side view of a measuring gauge formed in accordance with thepresent invention;

FIG. 2 is an end view of the measuring gauge shown in FIG. 1;

FIG. 3 is a top view of the measuring gauge shown in FIG. 1;

FIG. 4 is a side view of the measuring gauge's anchor;

FIG. 5 is a side view of the measuring gauge's adapter;

FIG. 6 is a side view of the measuring gauge's outrigger;

FIGS. 7-9 shown details of the locking joint's housing;

FIG. 10 shows details of the locking joint's locking screw;

FIG. 11 is a top plan view of a measuring gauge kit formed in accordancewith the present invention;

FIGS. 12-19 are schematic views showing how the measuring gauge may beused in a total hip replacement procedure;

FIGS. 20-22 show an alternative form of the measuring gauge; and

FIGS. 23-29 show another alternative form of the measuring gauge.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Looking first at FIGS. 1-3, there is shown a measuring gauge 5 whichgenerally comprises an anchor 100, an adapter 200, an outrigger 300 anda locking joint 400.

Looking next at FIGS. 1-3 and 4, anchor 100 preferably comprises ananchoring pin 105. Anchoring pin 105 generally comprises a body 110having a pointed distal end 115, a proximal end 120, and adiametrically-enlarged collar 125. Collar 125 terminates in a distal endsurface, or first shoulder, 130 and a proximal end surface, or secondshoulder, 135.

Looking next at FIGS. 1-3 and 5, adapter 200 preferably comprises a pinsleeve 205. Pin sleeve 205 generally comprises a body 210 having adistal end 215, a proximal end 220, and an interior bore 225 opening ondistal end 215 and extending at least part of the way, and preferablyall of the way, to proximal end 220. The internal diameter of interiorbore 225 is such that there is a frictional fit between pin sleeve 205and body 110 of anchoring pin 105. Preferably a handle 230 is attachedto proximal end 220 of pin sleeve 205.

Looking next at FIGS. 1-3 and 6, outrigger 300 preferably comprises abar portion 305 and a pointer portion 310. More particularly, barportion 305 comprises a first end 315 and a second end 320, and pointerportion 310 comprises a first end 325 and a second end 330. The secondend 320 of bar portion 305 is connected to the second end 330 of pointerportion 310 so that the two elements together form a generally L-shapedelement. The first end 325 of pointer portion 310 preferably terminatesin a point so as to constitute a pointer 335.

Looking next at FIGS. 1-3 and 7-10, locking joint 400 preferablycomprises a housing 405 and a locking screw 410.

Housing 405 has three bores formed therein: a first bore 415 extendingcompletely through housing 405, a second bore 420 also extendingcompletely through housing 405, and a third bore 425 extending at leastpartially through housing 405. More particularly, first bore 415, secondbore 420 and third bore 425 extend at right angles to one another, withfirst bore 415 and second bore 420 intersecting one another intermediatetheir respective lengths, and with third bore 425 intersecting secondbore 420 at the interior end of third bore 425. Third bore 425 isthreaded.

Locking screw 410 comprises a threaded shaft 430 and a head 435. Thelocking screw's shaft 430 is threaded, and is sized, so as to bereceived in the housing's third bore 425.

In practice, and as will hereinafter be discussed in further detail, itis intended that adapter 200, outrigger 300 and locking joint 400 mayall be assembled into an adjustable subassembly unit, which subassemblyunit may itself be mounted on, or dismounted from, anchor 100.

More particularly, it is intended that the aforementioned adjustablesubassembly unit be formed by extending the pin sleeve's distal end 215through the locking joint's first bore 415, and by passing the first end315 of the outrigger's bar portion 305 through the locking joint'ssecond bore 420, such that (1) when the locking screw's threaded shaft430 is advanced an appropriate distance into the locking joint's thirdbore 425, pin sleeve 205, outrigger 300 and locking joint 400 willconstitute a substantially rigid subassembly, and (2) when the lockingscrew's threaded shaft 430 is withdrawn an appropriate distance out ofthe locking joint's third bore 425, pin sleeve 205, outrigger 300 andlocking joint 400 may be adjustably positioned relative to one another.

Looking next at FIG. 11, measuring gauge 5 is intended to have itsconstituent components (i.e., anchor 100, adapter 200, outrigger 300 andlocking joint 400) packaged in a tray 500. Preferably tray 500 is filledwith the measuring gauge components at the time of manufacture, and thenthe tray is sealed with a transparent top tear sheet 505 so as to form apre-packaged kit which may thereafter be opened at the time of use. Asis well known in the art, tray 500 and its constituent components may besterilized either before or after the tray is sealed with top tear sheet505.

In one preferred form of the invention, anchor 100, adapter 200 andlocking joint 400 are pre-assembled together within tray 500, in themanner shown in FIG. 11, before the tray is sealed with top tear sheet505. In this position, the distal end 215 of pin sleeve 215 will engageand rest on the proximal end surface 135 of the anchoring pin's collar125.

Hip gauge 5 is intended to be used as follows.

Initially, the hip joint is surgically exposed in the traditionalmanner, so as to present the surgeon with access to the patient's femur600 and ilium 605 (see FIG. 12). Then a mark 615 (FIG. 12) is made onthe femur's greater trochanter 610, preferably using pointed distal end115 of anchoring pin 105. Preferably the depth of the mark is less than2 millimeters deep. If desired, this mark can be enhanced with sterileink. Alternatively, the mark may be placed on greater trochanter 610using some other device, such as a marking pen or an electrocauterydevice.

Next, the pointed distal end 115 of anchoring pin 105 is driven into thepatient's ilium 605 (see FIG. 13) by impacting on handle 230 of pinsleeve 205 with a mallet. Anchoring pin 105 is driven into the patient'silium 605 until collar 125 of the anchoring pin engages the outersurface of the ilium, whereupon further penetration of the anchoring pininto the ilium is prohibited. In general, a line extending between theentry point of anchoring pin 105 in ilium 605 and the mark 615 on femur600, is substantially parallel to the coronal plane of the patient'strunk.

At this point, outrigger 300 is attached to locking joint 400 (see FIG.14), by passing the first end 315 of the outrigger's bar portion 305through second bore 420 of the locking joint.

With locking screw 410 loose enough to permit adjustment of pin sleeve205 and outrigger 300 relative to locking joint 400, measuring gauge 5is manipulated so that pointer 335 of the outrigger is positioned on themark 615 previously made on the femur's greater trochanter (see FIG.15).

Once this has been done, the measuring gauge's locking screw 410 istightened so as to lock pin sleeve 205 and outrigger 300 in positionrelative to one another.

Then, the pin sleeve 205, outrigger 300 and locking joint 400 areremoved from anchoring pin 105 as a single locked unit, by withdrawingthe pin sleeve off proximal end 120 of anchoring pin 105 (FIG. 16). Thisleaves anchoring pin 105 secured in the patient's ilium 605 (see FIG.16), but with the hip joint fully exposed to the surgeon.

At this point, the surgeon proceeds forward with the total hipreplacement surgery in the traditional way, i.e., the hip is dislocated,the upper end of the femur is resected, and trial prostheses areinstalled in the femur and the acetabulum.

Once the trial prostheses have been installed in the patient, the hipjoint is reduced, permitting the surgeon to check for proper alignmentof the prostheses, any leg length discrepancy, proper lateral offset,and the stability of the hip joint from dislocation. This may be quicklyand easily accomplished using the present invention, i.e., byre-installing pin sleeve 205, outrigger 300 and locking screw 400 (whichare locked together as a single unit) back onto anchoring pin 105 andthen noting the position of the outrigger's pointer 335 relative to themark 615 previously made on the patient's femur (see FIG. 17). It shouldbe appreciated that when pin sleeve 205, outrigger 300 and locking screw400 are re-installed as a locked unit back onto anchoring pin 105, careis taken to ensure that the pin sleeve's distal end 215 engages theanchoring pin's collar 125, whereby measuring gauge 5 will occupyexactly the same position it previously occupied relative to thepatient's hip joint.

In some cases, the outrigger's pointer 335 may be perfectly aligned withthe mark 615 made on the patient's femur (see FIG. 17). In this case,the surgeon will know that the prosthesis is essentially restoring thehip joint to its original condition.

In other cases, the outrigger's pointer 335 may be longitudinallydisplaced from the mark 615 made on the patient's femur (see FIG. 18).In this case, the surgeon will know that the prosthesis is causing achange in the patient's leg length.

And in other cases, the outrigger's pointer 335 may be laterallydisplaced from the mark 615 made on the patient's femur (see FIG. 19).In this case, the surgeon will know that the prosthesis is causing achange in the lateral displacement of the patient's leg.

The surgeon can then take any such measurements into account as theoperation proceeds forward.

More particularly, pin sleeve 205, outrigger 300 and locking joint 400are thereafter removed as a locked unit from anchoring pin 105, apermanent prosthesis installed in the patient's femur, and then thejoint reduced again. Then measuring gauge 5 may be used to re-check theposition of the joint, by re-inserting pin sleeve 205, outrigger 300 andlocking screw 400, as a locked unit, over anchoring pin 105. Again, thispermits the surgeon to check for proper distal displacement and properlateral offset, by observing the position of the outrigger's pointer 335relative to the mark 615 made on the patient's greater trochanter. Ifthe surgeon finds that the position of the outrigger's pointer 335 isnot correct relative to the mark 615 made on the patient's greatertrochanter, the procedure can be repeated so as to install analternative prosthesis.

Once the surgeon is satisfied that the proper prosthesis has beenselected, pin sleeve 205, outrigger 300 and locking screw 400 isremoved, as a locked unit, from anchoring pin 105. Then anchoring pin105 is removed from the patient's ilium 605, and the total hipreplacement surgery proceeds forward in the traditional manner.

MODIFICATIONS OF THE PREFERRED EMBODIMENT

It is, of course, possible to modify the preferred embodiment discussedabove without departing from the scope of the present invention.

Thus, for example, outrigger 300 may be replaced by the outrigger 300Ashown in FIGS. 20-22. Outrigger 300A comprises a bar portion 305A and apointer portion 310A. More particularly, bar portion 305A comprises afirst end 315A and a second end 320A, and pointer portion 310A comprisesa first end 325A and a second end 330A. The second end 320A of barportion 305A includes a smooth bore 331A (FIG. 22), and a threaded bore332A (FIG. 22) which intersects bore 331A. Smooth bore 331A is sized toreceive pointer portion 310A, and threaded bore 332A is sized to receivea locking screw 333A (FIG. 22), whereby the outrigger's pointer portion310A may be adjustably positioned relative to the outrigger's barportion 305A. The first end 325A of pointer portion 310A preferablyterminates in a point so as to constitute a pointer 335A.

In use, outrigger 300A is used exactly the same as outrigger 300disclosed above, except that the position of pointer portion 310A may beadjusted relative to the position of bar portion 305A.

It is also possible to replace the locking joint 400 previouslydisclosed with an alternative form of locking joint. By way of examplebut not limitation, it is possible to replace locking joint 400 with thelocking joint 400A shown in FIGS. 23-29. Locking joint 400A generallycomprises a U-shaped housing 405 (FIG. 26) having a first bore 410formed therein, and a pair of legs 415. A second bore 420 is formed inlegs 415. Locking joint 400A also comprises a bolt 425 (FIG. 28) havinga bore 430 formed therein, and a nut 435 (FIG. 29) sized to fit on thethreaded end of bolt 425. The housing's first bore 410 is sized toreceive the measuring gauge's pin sleeve 205, and the housing's secondbore 420 is sized to receive bolt 425. The bolt's bore 430 is sized toreceive the bar portion 305 of outrigger 300 (or the bar portion 305A ofoutrigger 300A). As a result of this construction, by loosening nut 435on bolt 425, the positions of pin sleeve 205 and outrigger 300 (oroutrigger 300A) may be adjusted relative to locking joint 400A and,hence, relative to one another. However, by tightening nut 435 on bolt425, the relative positions of pin sleeve 205 and outrigger 300 (oroutrigger 300A) may be locked relative to locking joint 400A and, hence,relative to one another.

It should also be appreciated that, while in the foregoing description,the present invention has been discussed in the context of a total hipreplacement surgery, it is also possible to use the present invention inconnection with other joint reconstructions. Thus, for example, themeasuring gauge may be used in a total knee replacement surgery, or atotal elbow replacement surgery, etc.

It is also possible to use the present invention in surgeries involvingbones, but not necessarily involving joints.

In essence, the measuring gauge of the present invention may be used ina wide range of surgeries where the relative position of bones must bedetermined during such surgery.

ADVANTAGES OF THE INVENTION

Numerous advantages are achieved through the provision and use of thepresent invention.

For one thing, the present invention provides an improved apparatus forsimultaneously determining the distal displacement and lateral offset ofthe femur relative to the ileum.

And the present invention provides apparatus for simultaneouslydetermining the distal displacement and lateral offset of the femurrelative to the ilium, wherein the apparatus is adapted for easyinstallation and removal, whereby a major portion of the apparatus canbe temporarily removed from the surgical site so as to provideunobstructed access to the surgical site.

And the present invention provides apparatus for simultaneouslydetermining the distal displacement and lateral offset of the femurrelative to the ilium, wherein the apparatus is safe and effective touse in total hip replacement surgeries.

In addition, the present invention provides apparatus for determiningthe distal displacement and lateral offset of the femur relative to theilium, wherein the apparatus will reduce the amount of time normallyrequired to determine the distal displacement and lateral offset of thefemur relative to the ilium.

Also, the present invention provides apparatus for determining therelative position of bones during surgery, where the bones comprisebones other than the femur and the ilium.

And the present invention provides an improved method for measuring thedistal displacement and lateral offset of the femur relative to theilium.

Furthermore, the present invention provides an improved method fordetermining the relative position of bones during surgery.

What is claimed is:
 1. A measuring gauge for measuring the relativeposition of two bones during surgery, the measuring gauge comprising ananchor, an adaptor, an outrigger and a locking joint: said anchor beingadapted for attachment to a first bone of the patient; said adaptorbeing adapted for removable attachment to said anchor and comprising afirst axis; said outrigger comprising a pointer and a second axis; saidlocking joint having a first bore, a second bore, and a third boretherethrough, said locking joint being adapted for adjustable attachmentto said adaptor within said first bore such that said locking joint maybe selectively pivoted about and moved along said first axis; and saidoutrigger is adapted for adjustable attachment to said locking jointsuch that said outrigger may be selectively pivoted about and movedalong said second axis; whereby when said anchor is attached to thefirst bone of the patient, said locking joint may be selectively pivotedabout and moved along said first axis, and said outrigger may be pivotedabout and moved along its second axis, until said pointer is alignedwith a reference point located on a second bone of the patient, and thena single locking screw advanced an appropriate distance into said thirdbore of said locking joint may be adjusted so as to secure said lockingjoint to said adaptor and so as to secure said outrigger to said lockingjoint, whereupon said adapter, said locking joint and said outrigger maybe removed as a unit from said anchor.
 2. A measuring gauge formeasuring the relative position of two bones during surgery, themeasuring gauge comprising an anchor, an adaptor, an outrigger and alocking joint: said anchor being adapted for attachment to a first boneof a patient; said adaptor being adapted for removable attachment tosaid anchor and comprising a first axis; said outrigger comprising apointer and a second axis; said locking joint having a first bore, asecond bore, and a third bore therethrough, said locking joint beingadapted for adjustable attachment to said adaptor within said first boresuch that said locking joint may be selectively pivoted about and movedalong said first axis; said outrigger is adapted for adjustableattachment to said locking joint such that said outrigger may beselectively pivoted about and moved along said second axis; and saidfirst axis and said second axis extend at a substantially right angle toone another; whereby when said anchor is attached to the first bone ofthe patient, said locking joint may be selectively pivoted about andmoved along said first axis, and said outrigger may be pivoted about andmoved along its second axis, until said pointer is aligned with areference point located on a second bone of the patient, and then asingle locking screw advanced an appropriate distance into said thirdbore of said locking joint may be adjusted so as to secure said lockingjoint to said adaptor and so as to secure said outrigger to said lockingjoint, whereupon said adapter, said locking joint and said outrigger maybe removed as a unit from said anchor.
 3. A measuring gauge formeasuring the relative position of two bones during surgery, saidmeasuring gauge comprising an anchor, an adaptor, an outrigger and alocking joint: said anchor being adapted for attachment to a first boneof a patient and comprising a pin having a point at one end; saidadaptor being adapted for adjustable attachment to said anchor andcomprising a sleeve adapted to be mounted over said pin; said pincomprising first and second shoulders on said anchor, wherein saidsecond shoulder is spaced from said first shoulder, and further whereinsaid sleeve is adapted to contact said second shoulder when said adaptoris mounted on said anchor; said outrigger comprising a pointer; saidlocking joint having a first bore, a second bore, and a third boretherethrough, said locking joint being adapted for adjustable attachmentto said adaptor within said first bore; and said outrigger being adaptedfor adjustable attachment to said locking joint within said second bore;whereby said anchor is attached to the first bone of the patient, saidlocking joint may be selectively adjusted relative to said adaptor, andsaid outrigger may be selectively adjusted relative to said lockingjoint, until said pointer is aligned with a reference point located on asecond bone of the patient, and then a single locking screw advanced anappropriate distance into said third bore of said locking joint may beadjusted so as to secure said locking joint to said adaptor and so as tosecure said outrigger to said locking joint, whereupon said adaptor,locking joint and outrigger may be removed as a unit from said anchor.4. A measuring gauge for measuring the relative position of two bonesduring surgery, said measuring gauge comprising an anchor, an adapter,an outrigger and a locking joint: said anchor being adapted forattachment to a first bone of a patient; said adaptor being adapted forremovable attachment to said anchor; said outrigger comprising a pointerand a bar portion, wherein said pointer is adjustably mounted to saidbar portion; said locking joint having a first bore, a second bore, anda third bore therethrough, said locking joint being adapted foradjustable attachment to said adaptor within said first bore; and saidoutrigger being adapted for adjustable attachment to said locking jointwithin said second bore; whereby when said anchor is attached to thefirst bone of the patient, said locking joint may be selectivelyadjusted relative to said adaptor, and said outrigger may be selectivelyadjusted relative to said locking joint, until said pointer is alignedwith a reference point located on a second bone of the patient, and thena single locking screw advanced an appropriate distance into said thirdbore of said locking joint may be adjusted so as to secure said lockingjoint to said adaptor and so as to secure said outrigger to said lockingjoint, whereupon said adaptor, locking joint and outrigger may beremoved as a unit from said anchor.